Preparation Of Three-dimensional Porous Tin Dioxide Foam And Its Gas Sensing Properties

As a kind of ideal gas sensing material,SnO₂ is widely used in gas sensor.Usually,the gas-sensing properties of the material can be improved by doping and changing the morphology,3-D porous structure can increase the surface adsorption?reaction?space of gas sensing material,it can enhance the adsorption capacity of gas sensing material,and it is helpful to improve the gas sensing property of the material.In this paper,the preparation process of silicon-based SnO₂ foam and its gas-sensing properties for ethanol were studied.Firstly,Sn film were deposited on Si/SiO₂ substrates by electron beam evaporation method,and SnO₂ film were prepared by thermal oxidation method to enhance the adhesion between the films.Then,Sn film were deposited on Si/SiO2/SnO2 by magnetron sputtering method,and the Sn foam was deposited on Si/SiO₂/SnO₂/Sn by electrochemical deposition in an acidic electrolyte.Finally,the Sn foam was oxidized to SnO₂ foam by thermal oxidation.In this paper,the gas sensing elements of the 3-D porous SnO₂ foam material and the nano SnO₂ as the transition layer were prepared by the aluminum electrode.The gas sensing properties of two kinds of materials were tested.After the test,the temperature is 300?,the sensitivity of Sn O₂ foam material on 300ppm of ethanol is 37,and the SnO₂ nano materials just is 16 in the 300ppm ethanol gas,the optimum temperature of SnO₂ foam gas sensitive material is 300?,and the optimum temperature of nano SnO₂is 350?;in addition,SnO₂ foam has the advantages of short response/recovery time and good selectivity to ethanol gas.The results show that SnO₂ foam base on the silicon has a good gas sensing property to ethanol and it is better than the nano SnO₂ as the transition layer.